I had the opportunity to speak with one of Ingenuity's engineers in the NASA pavilion at the EAA Fly In in Oshkosh, WI in 2017 (or perhaps 2016). This was before it had been accepted for the Rover2020 mission but just after they had proven the concept flight capable. I asked him about flight conditions on Mars and what they had to do to get their design airborne in such a thin atmosphere. He made a few points.
1. Given the thinness of the atmosphere, the counter rotating blades are balanced among thickness, length, and rotation speed. They're essentially as big as they can spin with the power they have at a speed where the tips are just under the Martian speed of sound.
2. I asked if wind was an issue. He said that it wasn't an issue for the stability of the craft (Martian wind moving much of anything is a movie trope) but the turbulence it caused could be a major issue for the blades, as they're essentially small wings, like a helicopter. The turbulence of a cross breeze could disrupt the flow of air over the blades and cause them to lose lift.
3. The design of the craft was essentially locked once they confirmed it could fly. They would keep most of their original hardware and software, rather than rebuild anything, which I found surprising. Given this was before they were accepted on the mission I'm not sure if anything changed. It does appear to be pretty equivalent to what we saw there.
1. Given the thinness of the atmosphere, the counter rotating blades are balanced among thickness, length, and rotation speed. They're essentially as big as they can spin with the power they have at a speed where the tips are just under the Martian speed of sound.
2. I asked if wind was an issue. He said that it wasn't an issue for the stability of the craft (Martian wind moving much of anything is a movie trope) but the turbulence it caused could be a major issue for the blades, as they're essentially small wings, like a helicopter. The turbulence of a cross breeze could disrupt the flow of air over the blades and cause them to lose lift.
3. The design of the craft was essentially locked once they confirmed it could fly. They would keep most of their original hardware and software, rather than rebuild anything, which I found surprising. Given this was before they were accepted on the mission I'm not sure if anything changed. It does appear to be pretty equivalent to what we saw there.